The Net Investment Income Tax (§ 1411) and Its § 469 Interaction

The § 1411 Net Investment Income Tax imposes a 3.8% surtax that interlocks tightly with the § 469 passive rules, making the active/passive determination doubly consequential.

The computation

Under § 1411, the 3.8% applies to the lesser of net investment income or the excess of MAGI over the threshold ($250,000 MFJ / $200,000 single / $125,000 MFS). NII comprises three baskets: (1) interest, dividends, annuities, royalties, and rents; (2) income from a passive trade or business or a trading business; and (3) net gain from disposition of property, net of properly allocable deductions.

The ordinary-course / active exclusions

Income derived in the ordinary course of a non-passive trade or business is excluded. So the same § 469 material participation that makes business income non-passive also removes it from NII, a unified planning lever. Self-employment income subject to § 1401(b) and qualified plan distributions are also excluded.

The real estate professional interaction

For a real estate professional, a safe harbor (more than 500 hours in the rental activity for the year, or in 5 of the last 10 years) deems the rental income and disposition gain to arise in the ordinary course of a trade or business, excluding it from NII under § 1.1411-4. REPS plus material participation can therefore strip both the passive loss limitation and the 3.8% surtax.